Praxis' decimation resulted in a deadly pollution of Qo'noS' ozone, threatening the depletion of their oxygen within approximately fifty Earth years. Due to the Empire's enormous military budget, their economy did not have the resources with which to combat the catastrophe, forcing ChancellorGorkon to approach the Federation with an overture of peace. This set into motion a series of events, eventually resulting in a lasting peace between the Federation and the Empire. (Star Trek VI: The Undiscovered Country; VOY: "Alliances", "Flashback")

In Star Trek Into Darkness, the Enterprise journeys to Qo'noS, and a large moon fragment strongly resembling the remains of Praxis can be seen. Co-writer Alex Kurtzman stated "It certainly was inspired by Praxis, however, it's not specified, so we're leaving it open as to exactly what that moon was." [2]Roberto Orci agreed in a comment on Twitter, stating that the moon was "not specified as Paraxis [sic]. But could be" [3] The destroyed sole moon of Qo'noS was however identified as Praxis on screen in the table of information. [4]

Background materials for that film also mention Section 31 having a mysterious "Praxxis [sic] Project", which may or may not have anything to do with the moon. (see here and here).

In the Star Trek: Myriad Universes story The Chimes at Midnight, set in an alternate timeline (specifically, the one from TAS: "Yesteryear" in which Spock died as a child), Praxis is chosen by Thelin in 2290 as the test site for the Genesis Device (which in this timeline had led to full-scale war) both as a demonstration of force and because, with nearly all of its inhabitants living in areas either underground or shielded, there would be little or no loss of life. The action forces the Klingon surrender – unfortunately, the Genesis Wave overwhelms most shields and reaches below the ground, and of the population of half a million, only 2,000 survive. However, during peace negotiations, it is discovered that Genesis actually saved the moon, as the explosion which occurred in the prime universe had been inevitable within a year before the wave had strengthened the planet and put an end to the mining that would eventually destroy it.

In the novel Sarek by A.C. Crispin, in addition to polluting Qo'noS's atmosphere, Praxis's explosion has created a ring of debris around the planet that subjects the surface to constant, and sometimes deadly, meteor showers, which also makes space traffic to and from the planet extremely dangerous – another reason why the planet is becoming uninhabitable.

In Star Trek Online, Praxis is presented as the former moon of the Klingon homeworld Qo'noS. After events that occur prior to the year 2409 broke the Khitomer Accords, mining on the remnants of Praxis renewed. The remnants of Praxis orbiting Qo'noS are collectively referred to as the Praxis Belt.